1. Field of the Invention
A key signature actuator for a musical keyboard eases playing from music written with difficult key signatures by automatically actuating the sharps or flats in the key signatures.
2. Description of the Prior Art
The musical keyboard is structured so as to facilitate performance of music in the major diatonic key of C. As early as the fifteenth century, keyboard musical instruments have had a row of front digitals to play the diatonic scale and a row of back digitals to play other tones of the chromatic scale. The major mode of the diatonic scale is started with the C tone, played on a C front digital. The succeeding D, E, F, G, A, B tones are played on the succeeding front digitals.
The traditional way of writing music, used as early as the eleventh century, is to position symbols on a staff consisting of horizontal lines. The seven tones of the diatonic scale are now represented by notes on five-line staffs. Interspersed tones of the chromatic scale are referred to the notes of the basic diatonic scale by means of sharp or flat symbols which serve as corrections up or down from notes of the basic diatonic scale. Thus, a chromatic tone intermediate to the C and D tones is represented by C# or Db.
For a tonal musical composition to be written without the use of sharp or flat symbols, it must be written in the key of C. Such a restriction would severely limit the choice of a modern composer, for he probably wants to base his composition on a tonic above or below the C tone. This would be no problem for singers or for musical instruments having uniform pitch changers; but many musical instruments do not have such pitch changers. So composers and their publishers resort to a rather unsatisfactory method for specifying the absolute pitch of their diatonic scale--they start the major mode of their diatonic scale on some other note than C. This method requires that one or more of the seven diatonic notes be corrected by means of a sharp or flat symbol. The composer finds it convenient to specify these note corrections by means of a key signature that is placed at the front of each line of written music. Key signatures greatly reduce the effort needed to write modern music and to understand the written music.
In the case of a keyboard player, these key signature corrections are played on the back digitals. This detracts from the former virtue of the traditional keyboard of providing wide front digitals for the most commonly used tones, which are those of the diatonic scale. And having learned to play a musical composition written in one key, a keyboard musician finds that playing the composition written in a different key requires different fingering. Furthermore, the ordinary keyboard player has difficulty remembering and playing all the shapes or flats called for in the fourteen possible key signatures of written music.
To alleviate these difficulties, a keyboard instrument can be provided with a device to automatically actuate the tone corrections specified in the key signature. Such a device, which I call a key signature actuator, was disclosed in Martin Philipps in 1886 (U.S. Pat. Nos. 354,733, 466,907 and 519,071. If, for example, the device was set for a key signature with one sharp, then the F front digital would play not the F tone but the F# tone instead, as called out in the key signature. This century-old key signature actuator has not been widely used because of its mechanical complexity and expense. Indeed key signature actuators appear to be unavailable commercially.
Uniform pitch changers, which are widely available commercially, are generally used to change the pitch of the keyboard output away from the intended pitch of written music, perhaps to accommodate a particular singer or group of singers. However, for two seldom-used key signatures calling for seven sharps and seven flats (keys of C-sharp and C-flat) the musical composition can be played in the key of C and a uniform pitch changer can be used to change the pitch of the keyboard output to the intended pitch of the written music. The simple device does not work for the other twelve key signatures of written music, however, because in order to play a diatonic scale on the front digitals it would be necessary to associate a sequence of seven notes in the written music with a changed sequence of seven digitals of the keyboard.
It would of course be possible to rewrite all music in the key of C for the benefit of keyboard players possessing uniform pitch changers, but such rewritten music would not be satisfactory for playing on other instruments or on other keyboards not having uniform pitch changers. Thus rewriting the music in an easier key is not an entirely satisfactory solution to the problem of difficult key signatures.
Electrical versions of a key signature actuator are described in my U.S. Pat. Nos. 3,986,422, 4,640,173 and 4,048,893. In the last of these inventions the keyboard fingering of accidentals is quite different for different key signatures. The other two patents disclose key signature actuators that do not have this disadvantage, but they require two extra back digitals per octave span. All of these key signature actuators operate by altering the interdigital musical intervals of the tones played by a first set of front digitals.
Traditionally, the front digitals are identified by their position with respect to the groups of two or three back digitals, which serve as landmarks. Beginning keyboard students are taught to memorizs the letter labels for the lines and spaces of two musical staffs, to recognize the letter label for each note of written music, and to find its corresponding front digital on the keyboard using the grouping of the back digitals as landmarks. My copending patent application Ser. No. 921,407, U.S. Pat. No. 4,750,399 discloses a key signature actuator for the traditional keyboard which operates by associating notes of the written music with a set of movable keyboard landmarks, rather than with particular keyboard digitals. In operation of this key signature actuator, a uniform pitch changer is adjusted so that a "C" digital of the keyboard will sound the tonic of the written music, and at the same time the keyboard landmarks are bodily shifted along the keyboard, so that the key note of the written music will be played on that digital. This has the effect of automatically actuating the sharps and flats in the key signature of the written music.
In that disclosure one set of movable keyboard landmarks, which simulates the back digitals, uses seven separate electronic control modules for each octave span of the keyboard. Another set of keyboard landmarks, which simulates the musical staff lines, uses a separate electronic control module for each two front digitals of the keyboard. In manufacture of this device a large part of the cost is due to these many separate electronic control modules, since each of the control modules requires seven signal input leads and a majority of them have ten power output leads to separate landmark elements.
A key signature actuator greatly reduces the mechanical difficulty of playing from music written in other keys than C, because the most frequently used tones are again played on the wide front digitals of the keyboard. The mental difficulty of reading from written music is also reduced, so that the player can afford more attention to expressive aspects of the music.